Realizing High-Detectivity Near-Infrared Photodetectors in Tin–Lead Perovskites by Double-Sided Surface-Preferred Distribution of Multifunctional Tin Thiocyanate Additive

Tin–lead perovskite photodetectors are attractive alternatives to silicon counterparts for near-infrared photodetection, due to their outstanding optoelectronic properties, solution processability, and flexible compatibility. However, uncontrollable crystallization and easy oxidation problems of tin-containing perovskites severely hinder advances in their perfomance. Herein, we develop a high-detectivity near-infrared photodetector using a tailored tin-lead perovskite structure. Notably, we employ tin thiocyanate to form a double-sided surface-preferred distribution in tin-lead perovskites, in which the majority is located at bottom and top surfaces, and the tiny minority positioned inside the films. The tailored perovskite structure with the unique additive distribution significantly improves the film morphology and antioxidation ability. Finally, self-powered tin-lead perovskite photodetectors achieve a peak responsivity of 0.57 A W–1, a detectivity of 8.48 × 1012 Jones at 910 nm, and a large linear dynamic range of 213 dB, accompanied by an outstanding lifetime of 2300 h. This work opens up a new avenue to developing high-performance near-infrared photodetectors.